CLASS 8: IMPACTS IICofC POLS 405Spring 2011

Hurricanes and GCC Intergovernmental Panel on Climate Change (2007): “it is likely that

hurricanes will gradually become more intense as the climate continues to warm... There is no clear trend in the annual numbers of tropical cyclones.”

Al Gore: “hurricanes will continue to rise in both intensity and frequency from climate change.”

Gulf Coast Study (US Climate Science Prog 2008). “Climate change appears to worsen the region’s vulnerability to hurricanes, as warming seas give rise to more energetic storms. The literature indicates that the intensity of major storms may increase 5 to 20 percent.”

Today: Both Northern Hemisphere and South Hemisphere AND therefore overall Global hurricane activity has continued to sink to levels not seen since the 1970s.

Hurricane Katrina Discussion

Caused by Global Warming? If not, what was the cause?

in SST = Storms?

NO.

In Hurricane Intensity?

Yes. Cats 4/5 Hurricanes have increased since (at least) the ’70s. However, the question is why (or from what)?

Conclusions This new study suggests that in the Atlantic basin, global

warming from increasing GHGs will have little impact, or perhaps cause some decrease, in tropical storm and hurricane numbers.

Large-scale environmental changes in circulation, such as wind shear, as well as possibly moisture, are likely the dominant factors producing the reduced storm frequency.

These results support recent research showing that the primary driver of the recent increase in Atlantic hurricane numbers was the warming of the tropical Atlantic relative to the other tropical basins.

However, increases in Hurricane/Cyclone intensity is likely from increases in SST from global warming.

Biodiversity Loss 279 of 677 species examined (Nature, 2003),

showed telltale signs of human induced climate change.

On avg, these species had moved roughly 4 miles northward or 20ft in elevation per decade

Of 8 species of butterfly in NA and EU, all showed “sign switching”—that is, they moved north during the warm period of the early 20th C, then moved south mid-Century and now returned north. Non contradicted this pattern.

Large Scale Ecosystem Change

Shifting biomes (regions with similar traits) EU study shows biomes pushing north by 75

miles in last century. Widening Tropics Expanding deserts Expansion of boreal forests poleward into fast-

thawing tundra; likewise, southern edge of boreal forests turning to grasslands

Transitioning problems—climate may outrun the process—esp with forests

Insects

GCC, from increased temps, will facilitation the proliferation of parasitic insects, particularly mosquitoes

Increasing Vector Diseases from Mosquitoes Malaria: already infects ½ billion people each yr

(1/12 the human pop) and is 4 times higher than in 1990!

Dengue Fever: 2/5 of pop is exposed—and IPCC labels DF as the most imp vector borne disease (30 mil/yr) 1°C rise in temp could raise # exposed by 47%.

Rising Temperatures and Mosquitoes

Increased Malaria Risk

Dengue and Climate Change

* Dengue is transmitted by mosquitoes that have become perfectly adapted to the urban environment. Areas where there is poor sanitation and overcrowding (such as Rio de Janeiro, Brazil, right) are ripe for epidemics.

* Climate Change facilitates proliferation of the dengue vector

Forests and GCC

Deforestation huge impact on GCC, but how GCC affects forests is less understood.

Fires are expected to worsen with GCC, and in combo with beetle invasions (e.g. bark beetle) are leading to some of the world’s largest “forest die-offs”

“Both are unprecedented in modern records” (RG pp 159-60).

Mixed Effects to Agriculture Positives

Longer growing season Fewer days of frost More CO2 = increased plant food Plants ability to deal with drought (from CO2)

Negatives Geography plays major role—differing effects spatially Overall global loss in agricultural production Losses in key vulnerable areas—yields will drop in much

of the “poor” world Ramifications are significant—econ and political issue

Change in Agricultural Output Potential in 2080 Due to Climate Change

* Tropics: will affect 1-3 billion people with 10-20% declines in yields• North: Developed countries increase 3-10% in grain yields• North Am could see 3-13% increase in ag GDP, Russia 23% increase, while Africa could lose 5-17% of its agr yield.

Vids

Food and Climate Change

Climate Related Diseases kill Millions

Vulnerability

IPCC Def’n: “The degree to which a system is susceptible to, or unable to cope with, adverse effects of climate change, including climate variability and extremes. Vulnerability is a function of the character, magnitude, and rate of climate change and variation to which a system is exposed, its sensitivity, and its adaptive capacity.”

Basic: based on how processes and events of the ecological system influence the capacity of individuals and communities to cope and/or recover.

As a result, vulnerability can refer to a variety of places and scales. It can be: 1. the vulnerable system itself, such as low-lying islands (SIDS) or coastal

cities, 2. the impact to the system, such as flooding or forced migration, or 3. it can refer to the causal mechanism, such as melting permafrost or ice

break up in the Arctic.

Criteria for Vulnerability There is significant crossover from well-being to vulnerability, in that

there is a negative correlation between them. That is, the greater a population’s well-being (i.e. that basic needs are satiated), the less vulnerability (both present and future), and vice versa. Generally, this relationship holds true because those who have high levels of ‘well-being’ generally have the economic and social capacity to mitigate vulnerability.

7 IPCC criteria for identifying key vulnerability variables. magnitude of impacts timing of impacts persistence and reversibility of impacts likelihood (estimates of uncertainty) of impacts and vulnerabilities and

confidence in those estimates potential for adaptation distributional aspects of impacts and vulnerabilities importance of the system(s) at risk

Human Security Approach to Vulnerability

To Adapt or Mitigate? Mitigation: is the reduction of greenhouse

gas emissions entering earth’s climate system (thereby reducing the impact of climate change)

Adaptation: is the capacity to address the output or effects from climate change.

Current regime sees these as separate but connected spheres, with the focus today on mitigation.

a) Static current adaptive capacity; b) enhanced adaptive capacity; c) mitigation via emissions caps (550ppm); d) mitigation cap (550ppm) + enhanced adaptive capacity

Global Distribution of Vulnerability to GCC in 2050

a) Static current adaptive capacity; b) enhanced adaptive capacity; c) mitigation via emissions caps (550ppm); d) mitigation cap (550ppm) + enhanced adaptive capacity

Global Distribution of Vulnerability to GCC in 2100